A state-of-the-art laser heterodyne light-scattering apparatus will be employed to determine the viscoelastic properties of phospholipid monolayer-covered subsolutions to shed further insight into the nature of the interaction of calcium ions with the anionic lipid sites in biological membranes. Lecithin, phosphatidyl ethanolamine, phosphatidyl serine, phosphatidic acid, phosphate ester, cholesterol, and stearic acid monolayers will be studied on calcium-containing subsolutions.